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| author |   Melissa Wen <mwen@igalia.com> | 2022-03-29 19:18:35 -0100 |
|---|---|---|
| committer |   Alex Deucher <alexander.deucher@amd.com> | 2022-04-07 16:34:32 -0400 |
| commit | 67229b27ed6fdb6bfce04f61ce4026c57b32ba15 (patch) | |
| tree | 3267ccc2332f176fce24ddd3d6003825f5f2957a /drivers/gpu/drm/amd/pm/amdgpu_pm.c | |
| parent | drm/amdkfd: Improve concurrency of event handling (diff) | |
| download | linux-dev-67229b27ed6fdb6bfce04f61ce4026c57b32ba15.tar.xz linux-dev-67229b27ed6fdb6bfce04f61ce4026c57b32ba15.zip | |
drm/amd/display: don't ignore alpha property on pre-multiplied mode
"Pre-multiplied" is the default pixel blend mode for KMS/DRM, as
documented in supported_modes of drm_plane_create_blend_mode_property():
https://cgit.freedesktop.org/drm/drm-misc/tree/drivers/gpu/drm/drm_blend.c
In this mode, both 'pixel alpha' and 'plane alpha' participate in the
calculation, as described by the pixel blend mode formula in KMS/DRM
documentation:
out.rgb = plane_alpha * fg.rgb +
(1 - (plane_alpha * fg.alpha)) * bg.rgb
Considering the blend config mechanisms we have in the driver so far,
the alpha mode that better fits this blend mode is the
_PER_PIXEL_ALPHA_COMBINED_GLOBAL_GAIN, where the value for global_gain
is the plane alpha (global_alpha).
With this change, alpha property stops to be ignored. It also addresses
Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1734
v2:
* keep the 8-bit value for global_alpha_value (Nicholas)
* correct the logical ordering for combined global gain (Nicholas)
* apply to dcn10 too (Nicholas)
Signed-off-by: Melissa Wen <mwen@igalia.com>
Tested-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Tested-by: Simon Ser <contact@emersion.fr>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu/drm/amd/pm/amdgpu_pm.c')
0 files changed, 0 insertions, 0 deletions